Some vehicles, such as rail vehicles, may undergo tunneling operation in which the vehicle travels through a confined space, such as a tunnel. During tunneling operation, temperatures of various components of the vehicle, such as an engine, an aftertreatment system, and a cooling system, may increase. In some examples, the temperatures may increase substantially, leading to decreased power and overheating of the engine of the rail vehicle.
In one example, during tunneling operation, due to induction of exhaust gas from its own engine, from the exhaust of other engines in a train to which the vehicle is coupled, or from other engines which previously operated in the tunnel, a temperature of exhaust gas from the engine increases and a level of engine out soot increases. As such, a temperature of the aftertreatment system increases and a loading rate of an aftertreatment device of the aftertreatment system increases. When the aftertreatment device is overloaded with soot, clogging of the aftertreatment device may occur, resulting in increased backpressure on the engine which can eventually choke and shut down the engine. Further, when combustible material such as soot overloads the aftertreatment device at high enough temperatures, the soot may begin burning and the reaction may run away (e.g., runaway regeneration), leading to degradation of the aftertreatment system.